This question: $1$ point$($s$)$ possible

A$.$ It is usually less risky to use single suppliers rather than multiple suppliers.

B$.$ When multiple suppliers are used, having geographically centralized suppliers could lessen the probability of all failing simultaneously.

C$.$ The risk mitigation effectiveness of using multiple suppliers has nothing to do with the probability of a super$-$event occurring.

D$.$ When multiple suppliers are used, having geographically dispersed suppliers could lessen the probability of all failing simultaneously.